Gas turbine engines employ fuel injectors for providing fuel into the combustor of the turbine engine. Fuel injectors generally have an external body with an inlet at one end for receiving fuel and a fuel nozzle for providing the fuel to the combustor. An inner tube may be in fluid communication with the inlet and the fuel nozzle to deliver fuel received at the inlet of the fuel injector to the fuel nozzle. The combustor uses atomized fuel to run the turbine engine.
The fuel nozzle discharges an air-fuel mixture into the combustor causing combustion that creates a hot pressurized exhaust gas. Certain fuel nozzles employ a diaphragm which may be in contact against a seat component of the fuel nozzle. The seat and diaphragm may be contained near the tip of the fuel nozzle such that during fuel flow operation the surrounding metal may be exposed to the hot gases within the gas turbine combustor. As such, high metal temperatures may be experienced in the nozzle body, seat and diaphragm. Additionally, thermal shifts in fueling may occur due to changes in the modulus of elasticity of fuel nozzle components when operating at high metal temperatures.
Shifts in fueling at high operating temperatures and variability in nozzle to nozzle fueling may affect the life of turbine engine components. The fueling shift at increased temperatures may be problematic, especially if the engine might experience two phase flow within the fuel system. Thus, two phase flow may be a concern particularly in engines configured to run high temperature fuel through the fuel nozzle.